Australia counter-terror police kill man after two officers stabbed

SYDNEY (Reuters) - Australian police said they shot dead an 18-year-old man after he stabbed two counter-terrorism officers, just days after sweeping raids involving hundreds of police thwarted what they said was an imminent plot to behead a member of the public.

The man was asked to attend a police station in the southern state of Victoria because his behavior was "causing concern," according to Luke Cornelius, the Assistant Commissioner of Victoria Police.

"It's believed that an altercation has occurred in the vicinity of the police station involving the two police officers and that male person, and in the course of that altercation, the male person has produced an edged weapon," Cornelius said in a press conference late on Tuesday.

Police said the man had been displaying flag linked to the Islamic State while local media reported he had been shouting insults about Prime Minister Tony Abbott and the government before he was shot and died.

On Monday, Abbott warned Australians the balance between freedom and security "may have to shift", given the darkening security situation as he outlined broad new security powers expected to be introduced to parliament on Wednesday.

Australia is concerned over the number of its citizens believed to be fighting overseas with militant groups, including a suicide bomber who killed three people in Baghdad in July and two men shown in images on social media holding the severed heads of Syrian soldiers.

Abbott has said that at least 100 Australians are in the Middle East either fighting with or supporting Islamic State or other militant groups, a number that he said has increased in recent months.

At least 20 are believed by authorities to have returned to Australia and pose a security risk, and earlier this month the national security agency for the first time raised its four-tier threat level to "high".

More than 800 police were involved in the security operation in Sydney and Brisbane last Thursday, which authorities said had thwarted a plot by militants linked to the Islamic State group to behead a random member of the public.

Security last week was also boosted at Parliament House in Canberra, after intelligence "chatter" had revealed a plot to attack the building and politicians on orders from overseas militants.